Preparation and characterization of surface-modified montmorillonite by cationic surfactants for adsorption purposes

In this study, surface modification of montmorillonite with three types of cationic surfactants was investigated by adding different levels of surfactants corresponding to the CEC (cation exchange capacity) of montmorillonite; the surfactants were tetradecyl trimethylammonium bromide, cetyl trimethylammonium bromide, and didodecyl dimethylammonium bromide. Moreover, montmorillonite and modified montmorillonites were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy, thermal analysis, contact angle, and zeta potential. Their surface morphologies were also determined by using the field emission scanning electron microscopy. The basal spacing of montmorillonite increased after intercalation of cationic surfactants, while the maximum basal spacing was influenced by increasing the molar mass of the surfactant. Also, for the same surfactant, maximum basal spacing enhanced when the CEC increased from 1:0 to 2:0. The results of Fourier transforms infrared spectroscopy indicated that intercalation of surfactants between montmorillonite layers leads to changes in functional groups of modified montmorillonite. To summarize, we successfully modified montmorillonite, making it a potential nanoadsorbent that could be used for the adsorption of valuable compounds such as phenolic compounds from wastewaters and byproducts of food industries.